CHANGING CHARACTER OF POOL –RIFFLE SEQUENCE: A QUANTITATIVE REPRESENTATION OF LONG PROFILE OF ICHAMATI, INDIA

Abstract: The river Ichamati, which drains the eastern part of the district North 24 Pgs. W.B., India, has been analyzed regarding its long profile of the two years( 2004 and 2012) based on two windows. This paper has focused on the character of long profile such as, pool-riffle sequence and deviation index, which reveal the evolutionary tendency of long profile. Bed deformation technique (bdt) has identified the number and position of the pool and riffle on the riverbed. The classification of pool and riffle has been done with the help of tolerance value (T). The magnitude of T values is different in two windows. According to tolerance value (T), the position and number of pool and riffle has been changed significantly in two windows in two years. The threshold value of T has also been differed from 2004 to 2012. All these indicate the gradual decay of the river Ichamati.

Keywords: windows, long profile, pool-riffle sequence, deviation index, evolutionary tendency, Bed deformation technique, tolerance value.